What does a step response characterize in control systems?

A step response characterizes the output reaction of a control system to a sudden change in input. When a step input is applied, it represents an instantaneous change from one value to another, typically from zero to a certain magnitude. This sudden input allows technicians and engineers to observe how quickly and effectively the system responds to changes, providing valuable insights into the system's dynamics, stability, and time constants.

Understanding the step response is critical when analyzing the transient behavior of a control system, which encompasses how the output behaves immediately after the input change and how it evolves towards a new steady-state condition. This aspect is essential for designing and tuning control systems to ensure they meet the required performance specifications in terms of speed, stability, and accuracy.